What does missing someone feel like? Or loneliness?

Well, imagine you're a small child at the park.

You went there with someone you know, but you can't remember anything before they disappeared. You've been calling out their name for ages, and you can't see them anywhere. You end up asking other people where they are, but they don't have enough time for you. They're busy, just like everyone else you ask.

Loneliness is that feeling. The feeling when you sink to the floor and cry and shout and call their name.

Missing someone, well, it's that realisation that they might never come back, and you'll be alone forever.

I mean, that's how I'd describe it.